Last year, 18% of all arriving air passengers to the U.S. were "precleared" at foreign airports.

What's a speedy way to avoid long waits to enter the United States? Enter the U.S. outside the U.S.

U.S. Customs and Border Protection is looking to expand an oft-overlooked program that inspects incoming passengers at foreign airports. Last year, 14.8 million people, or 18% of all international air arrivals, were inspected and cleared by U.S. officers stationed at airports in other countries. Once cleared at one of 14 foreign...